Siphoning air lift tube



May 4, 1948. R. D. scATTERGoOD SIPHONING AIR LIFT TUBE Filed March 7, 194e I 11 z'elltor Patented May 4, i948 UNITED STATES PATENT oFElcE SIPHONING AIR LIFT TUBE Richard D. Scattergood, Philadelphia, Pa.

Application March 7, 1946, Serial No. 652,777

4 Claims. (Cl. 10S-232) This invention relates to improvements in air lift tubes for use in conjunction with outside aquarium filters.

All air lift tubes mentioned in the following text refer to those used in conjunction with outside lters, that is, lters located outside of the aquarium or tank.

An object of the invention is to provide an improved air lift tube which will circulate practical quantities oi water while using a negligible quantity of air, at pressures so low that ordinary air lift tubes fail completely to operate.

An object of the invention is to provide an improved air lift tube which when operated under higher air pressure is very much more eicient than ordinary air lift tubes.

A further ob-ject of the invention is to provide an improved air lift tube which will be highly eflicient in use and relatively inexpensive to manufacture and produce. By its use an aquarist who employs outside filters operated by compressed air will be enabled to save a considerable quantity of air, which he may employ for increased aeration, or to add more filters, or he may employ a less expensive air pump.

Other objects will appear as the description proceeds.

In the accompanying drawings which form a part of this application,

Figure l is a perspective View of the improved air lift tube;

Figure 2 is a vertical sectional View through the walls of two adjacent tanks showing the improved air lift tube in position therein, and

Figure 3 is a sectional View taken on the line 3-3 of Figure 2.

Like characters of reference are used throughout the following speciiication and the accompanying drawings to designate corresponding parts.

In carrying out the invention, there is provided an improved air lift tube formed of a glass or plastic tube, the same being bent to the shape of an inverted U having an upwardly extending inlet leg l open at its bottom, and a laterally extending section 2 which is bent downwardly to form the leg 3 to extend to the approximate level of the bottom of the leg l. The lower end of the leg 3 is then bent as at 4 and is extended upwardly to form the outlet leg 5 which terminates a considerable distance below the water level in the tank 6.

The term air lift tube as used in this specification applies to a. piece of tubing in which 2 water is displaced by means of air introduced at or near one extremity of the tube.

The filter tank 'l is placed adjacent the main tank 6, and the air lift tubeas above described is placed in position as shown in Figure 2, with the inlet leg I extending down into the iilter tank 'l and the downwardly extending leg 3 and outlet leg 5 are positioned within the main tank or aquarium 6.

lA glass or plastic spacing and reinforcing element comprises the spaced collar 8 and 9 with a connecting link portion l0, said collars being adapted to slip over the legs 3 and 5, as clearly shown in Figure 2 of the drawings.

A small glass or plastic compressed airtube is connected at its lower end with the lower end of the outlet leg tube 5 and is bent to lie adjacent the intermediate tube 3, and also extends through thecollar 9 of the spacing and reinforcing element. The compressed air tube Ii extends a considerable distance above the section 2 of the air lift tube, and may be fused or otherwise suitably connected to the side of the leg 3, if desired. A flexible rubber tube l2 will be placed over the end of the tube Il and will be connected with any suitable compressed air compressing machine y (not shown). Y

The three legs of the air lift tube will extend parallel to each other, and will also be spaced one from another. l

All other known types of air lift tubes used in conjunction with outside aquarium lters require that the tank or aquarium 6 be completely iilled with water in order to operate with any degree l of efficiency, whereas the design of the instant invention permits the water level in the tank or aquarium 6 to be as low as the upper extremity of the outlet leg 5 without any eiciency loss whatsoever.

The design of the improved air lift tube is such that Water is not lifted from the filter, such as tank l, back into the aquarium, as is the case with all known air lift tubes, but instead the improved air lift tube circulates the water through a Siphon. This is one of the principal reasons why the improved air lifttube uses less air and operates at a lower air pressure than any other. In all other known types of air lift tubes the curved portion of the tube forces the air bubbles to move downwardly in order to escape through the outlet, Whereas the design of the instant invention causes the air bubbles to move only straight up. This is another fundamental reason why the improved air lift tube uses less air and operates at a lower air pressure than any other.

The Vconstruction of the improved air lift tube permits a complete range of adjustment as to the quantity of water circulated, all the way from zero to maximum, by varying the quantity ci compressed air admitted. Regardless of air pressure or quantity, however, it always operates steadily, giving an even ilow of water. Standard air lift tubes, however, will not begin to operate until a muchhigher pressure of compressed air is admitted, at whichtime they will only cough and "spit and only spout out water, unless the air pressure is increased suiciently to give them a vsteady flow. Thus their range of adjustment is considerably more limited.

` Of course, an ordinary siphon (not shown) Ywill be used to replace water from the aquarium tank 6 to the lter tank 1, as it is drawn off bythe air lift tube. The siplion therefore tends to keep the.

water level even in the two tanks at all times.

From the foregoing description, it will be apparent that there has been devised a highly efcient form ofair lift tube, which will circulate a vmax'imum amount of water between two adian cent tanka'andl whose construction completely eliminates lift and downwardly moving air bubbles.

VWhile the preferred embodiment of the invention Yhas been illustrated as described, it will be understood that it is not intended to limit the scopeeof` the invention thereto, as many minor changes in detail of construction may be resorted to without departure from the Vspirit of the invention.

Having thus described my invention what I claim as new and desire to secure by Letters Patent ofthe United States is:

Ii air lift tube including `a body having an inlet legr open at its bottom, an outlet leg formed integrally therewith and open at its top, a compessed'air supplying tube connected with the lower end of said outlet leg, means for supplying compressed air to said compressed air supplying compressed air to said compressed air supplying tube, an intermediate tubular leg formed integrally with and disposed between said inlet and zoutlet legs, means for securing said compressed air supplying tube to said intermediate tube, and a spacing and reinforcing member including spaced collars adapted to be slidably received over said outlet tube and said compressed air supplying tube and intermediate tube.

3. An air lift tube including a body having an inlet leg open at its bottom, an outlet leg open atits top, an intermediate tubular leg formed Yintegrally with and disposed between said inlet and outlet legs, a compressed air supplying tube secured to said intermediate leg and extending between the same and said outlet leg being connected with the lower end of said outlet leg to reinforce said lift tube, and means for supplying compressed air to said compressed air supplying tube.

4. An air actuated liquid circulator comprising an inverted, substantially U-shaped tube constituting a siphon including a pair of connected, downwardly disposed legs adapted to be submerged in separate tanks having liquid therein at substantially the same common level, one of said legs having an open lower end and being disposed within one of said tanks with its lower open end below the liquid level therein, and the other of said legs being disposed Within the other of said tanks with the lower end thereof below the liquid level therein, and an air lift tube connected with the lower end of said last mentioned ieg and disposed within said last mentioned tank, said air lift tube comprising an upwardly-extending leg with the open upper end thereof discharging upwardly and below the liquid level in said last mentioned tank, and an air line com municating with the lower end of said air lift tube for supplying compressed air thereto.

RICHARD D. SCATI'ERGOOD.

REFERENCES CiTED The following references are of record in the file or" this patent:

UNTED Number Name Date 44,876 McKnight Nov. 1, 1864 779,941 Hughes Jan. 10, 1905 1,655,082 Rogers Mar. 4, 1913 1,319,797 Rogers Oct. 28, 1919 1,537,264 Rogers May 12, 1925 1,647,367 Kramer Nov. 1, 1927 

